拟南芥长链脂肪醇氧化酶(AtFAO3)在抗病防卫反应中的作用分析

长链脂肪醇氧化物酶(FAO)基因编码一个与膜结合,包含黄素,产生H_2O_2的长链脂肪醇氧化酶.在拟南芥基因组中包含4个FAO同源基因.然而,拟南芥FAO在响应非生物和生物环境胁迫中起何种作用还不得而知.本研究中,我们分析了拟南芥AtFAO3在植物防卫病原细菌Pseudomonas syringae pathovar(pv.)tomato strain DC3000(Pst DC3000)中的作用.拟南芥原生质体细胞瞬时表达AtFAO3偶联GFP融合蛋白表明,AtFAO3定位于细胞膜.与野生型植株相比,拟南芥AtFAO3基因T-DNA插入突变体Atfao3在正常条件叶片中H_2O_2含量下降,在氧胁迫或生物胁迫下积累活性氧含量减少.接种病原细菌Pst DC3000后,与野生型植株相比,Atfao3突变体体内细菌繁殖数量增加,叶片病害症状加重,防卫相关基因PR1、PR2和PAL表达减弱.我们基于以上T-DNA突变体分析结果表明,AtFAO3在植物对病原细菌防卫中起重要作用.

Functional Analysis of Arabidopsis AtFAO3 in Defense Against Pseudomonas syringae

The long-chain alcohol oxidase(FAO) gene encodes a membrane bound,flavin-containing,hydrogen peroxide generating,long chain alcohol oxidase.There are four homologues of FAO in the Arabidopsis thaliana genome.But very little information is known about the function of Arabidopsis FAOs in response to abiotic and biotic environmental stresses.Here,we analyzed the role of the AtFAO3 from Arabidopsis in plant defense against the bacterial pathogen Pseudomonas syringae pathovar(pv.)tomato strain DC3000(Pst DC3000).AtFAO3 translational fusion with green fluorescent protein(GFP)was localized to the cell membrane in Arabidopsis protoplast cells.T-DNA insertion mutants of Atfao3 displayed less H_2O_2 content in leaves under controlled conditions and accumulated less ROS levels under oxidative or biotic stress,compared to wild-type(WT)plants.Responded to bacterial pathogen,Atfao3 mutant increased growth of Pst DC3000 and displayed a increased severity of disease symptoms as compared to WT plants.The Atfao3 mutant plants also exhibited reduced expression of the defense-related PR1,PR2 and PAL genes after pathogen infection.On the basis of analysis of T-DNA insertion mutants,we confirmed that AtFAO3 played a key role in defense against bacterial pathogens.